In its first statement of substance on the ongoing investigation into CSE Corp.’s potentially faulty emergency miner breathing devices, the U.S. Mine Safety and Health Administration has suggested mine operators might consider trying a different product.

Yesterday, MSHA issued a new Procedure Instruction Letter that described replacing the CSE SR-100 as one way for mine operators to deal with this problem:

Mining companies utilizing these units may need to make adjustments to provide miners with the required number of SCSRs to comply with 30 C.F.R. Part 57 and 75. Purchasing units from a different manufacturer to meet the required number of SCSRs is acceptable provided all miners have received required training on the new units. If all manufacturers of SCSRs have exhausted their inventory and mining operators cannot obtain adequate supplies, MSHA will accept purchase orders with a confirmed delivery date of 60 days. While waiting on delivery of SCSRs, MSHA coal personnel will ensure that workers on coal mining sections are provided with the required number of units borrowed from SCSR caches located the farthest outby from the working sections.

Recall that back in February, MSHA disclosed the existence of an investigation into problems with the oxygen quick-starter on the SR-100s, saying at the time that it would recall about 4,000 of the units. It turned out the problem may be much bigger — and that CSE hasn’t actually removed any of the potentially defective units from the nation’s coal mines.

In its new PIL, MSHA described the underlying issues with the SR-100 this way:

Through its quality control program, CSE Corporation identified a possible issue with a component part to its SR-100 Self-Contained Self-Rescuers (SCSRs) involving a shipment of oxygen cylinders from its supplier. CSE is investigating the potential that the breathing bag may receive less than the optimum amount of oxygen necessary for full inflation, if the unit is started with the oxygen cylinder. Until the root cause is determined and corrected, CSE Corporation is temporarily suspending sales of the SR-100 SCSRs

A government photo shows the SCSRs that Sago miners tried to use to survive after the January 2006 explosion.

The SR-100 model uses a chemical process to generate the oxygen needed for a 60-minute supply of breathable air. Generally, the SR-100 units are started by pulling a large orange tab that activates an oxygen cylinder. The cylinder inflates a breathing bag. Once a miner starts breathing through the bag, the exhaled gases react with the unit’s chemicals to generate more oxygen for the miner.

SR-100s can also be started manually if the oxygen cylinder fails to inflate the breathing bag. But that process involves breathing ambient air — which could be full of smoke — and exhaling into the mouthpiece to start the chemical reaction.

As I’ve written before:

Over the years, coal miners have complained repeatedly about SCSRs not starting or appearing to start slowly. Government and industry officials have generally dismissed those complaints. They said miners were not properly trained and did not understand how their SCSRs worked.

Months after the Sago disaster, survivor Randal McCloy said the SR-100s of four of the 12 miners trapped by the Jan. 2, 2006, explosion would not start. McCloy described how he tried especially hard to start the rescuer that belonged to his mining partner, Jerry Groves, who eventually died of carbon monoxide poisoning.

“I fought with it for I don’t know how long, trying to mess with that valve, blow air through it, or anything I could do, but nothing would work,” McCloy told investigators.

In lawsuits filed after the disaster, Sago miners’ families were investigating concerns that the SR-100 oxygen cylinders — made by South African-based African Oxygen Ltd. — somehow leaked, leaving them without enough oxygen to properly start the units. Most of the suits against CSE have been settled, court records show.

I asked MSHA officials if they were encouraging companies to abandon the CSE devices, and agency spokeswoman Amy Louviere told me in an e-mail message:

Until we resolve the technical problems associated with CSE units, we want to make sure that mine operators know there are other options available.